The prior art embraces a packet of rigid type as disclosed in European patent EP 0 545 723, to which reference may be made for a full description, intended to hold a group of cigarettes enveloped previously in a respective inner wrapper of metal foil paper. The packet comprises a container with an internal stiffening frame, also a lid hinged to the container and rotatable about the respective hinge line between an open position affording access to the container, and a closed position in which the lid fits snugly over the frame and is held thus stably in place. The packet in question presents a cross section of substantially flattened oval profile and is fashioned from a flat precreased diecut blank referable to a predominating axis disposed transversely to the axis of the finished packet and presenting a plurality of panels, aligned along the selfsame axis, destined to provide both the sides of the container and of the lid, and the internal frame.
Also forming part of the blank are two pairs of end folds, each presenting an outline of substantially flattened oval profile, aligned in two sets of two along the aforementioned transverse axis and providing the elements by which the top end and bottom end faces of the packet are fashioned.
Besides being unsuitable for use on today's high speed packer machines, which will only handle blanks exhibiting a transverse dimension decidedly less than the longitudinal dimension, the type of blank described above can also be affected by the problem of incorrect mutual positioning between the outer wrapper and the inner wrapper. In effect, given the particular geometry of the blank, the packet is fashioned by bending the blank about an axis perpendicular to the transverse axis and rolling it gradually into a tube around the inner wrapper, interacting in the process with the selfsame inner wrapper, to the point of assuming the aforementioned substantially flattened oval profile. Thus, the inner wrapper functions to all intents and purposes as a mandrel around which the blank is formed by degrees.
It has been found by experiment that this type of wrapping operation can occasion relative movement between the inner wrapper and the outer wrapper, resulting in the drawback mentioned above and consequently in a loss of the correct mutual positioning between the two wrappers.
The object of the present invention is to overcome the above noted drawbacks.
It is also known, from document U.S. Pat. No. 5,392,905, a hinged lid packet for cigarettes which comprises a pack part and a lid pivotally attached to the pack part. The pack part presents a front panel, a rear panel, two lateral panels and a bottom; the lid comprises a lid front panel, a lid rear panel, two side panels and an end panel. The four longitudinal edges of the packet are rounded and are defined by a plurality of parallel grooves. The packet is formed from a first blank presenting a central panel, two intermediate panels and two end panels. The intermediate panels, which form the bottom and the end panel of the packet, present a substantially rectangular shape with rounded edges. The packet further comprises a collar formed from a separate blank.